Research Article: Prediction of vascular access stenosis: Blood temperature monitoring with the Twister versus static intra-access pressure ratio

Date Published: October 29, 2018

Publisher: Public Library of Science

Author(s): Yoo Jin Choi, Young-Ki Lee, Hayne Cho Park, Eun Yi Kim, Ajin Cho, Chaehoon Han, Sun Ryoung Choi, Hanmyun Kim, Eun-Jung Kim, Jong-Woo Yoon, Jung-Woo Noh, Micah Chan.


The Kidney Disease Outcomes Quality Initiative (KDOQI) guidelines recommend intra-access flow (Qa) measurement as the preferred vascular access surveillance method over static intra-access pressure ratio (SIAPR). Recently, it has become possible to perform Qa measurement during hemodialysis using thermodilution method called blood temperature monitoring (BTM) with the Twister device. The aim of this study was to investigate the correlation between Qa by BTM and SIAPR and to compare the performance of two tests in prediction of vascular access stenosis.

The study was performed from January 2016 to November 2017 and included 97 patients with arteriovenous fistulas (AVF). Qa by BTM and SIAPR were simultaneously measured every 1~3 months with a total of 449 measurements during study period.

In our study population, mean age was 59.9±10.0 years and 61.9% were diabetes. The mean Qa obtained by BTM was 1186±588 mL/min. There was no correlation between Qa by BTM and venous SIAPR (r = 0.061, P = 0.196). Angiography identified 36 stenotic AVFs (37.1%) among the study subjects. They included 13 cases with only inflow stenosis, 6 with only outflow stenosis, and 17 with stenosis on both sides. Receiver-operating characteristic (ROC) curve analysis showed that Qa by BTM had higher discriminative ability to diagnose vascular access stenosis compared to SIAPR (P <0.001). The Qa less than 583 mL/min showed the highest diagnostic accuracy in vascular stenosis prediction. Intradialytic measurement of Qa by BTM showed better diagnostic power over venous SIAPR in prediction of vascular access stenosis.

Partial Text

The function of vascular access is very important for optimal management in hemodialysis (HD) patients. Insufficient flow by vascular access stenosis cause inadequate dialysis or access thrombosis if not identified and treated in a timely fashion. Angiography is the gold standard modality to identify and characterize stenotic vascular lesions, but it is expensive and invasive. Radiocontrast media may reduce residual renal function in HD patients. Therefore, several non-invasive assessment tools were developed to observe the flow, pressure or recirculation process in vascular access during HD.

Mean age of the patients was 59.9±10.0 years, and 50.5% were male. A history of diabetes mellitus was present in 61.9%. Table 1 summarized the most important clinical characteristics of the subjects. The mean Qa by BTM was 1186±588 mL/min (range: 166~3085 mL/min), and the mean values of SIAPR was 0.34±0.17. Patients with diabetes and forearm AVF showed significantly lower Qa (Table 2). However, other clinical variables did not significantly affect Qa.

In conclusion, venous SIAPR neither correlated with Qa nor had a diagnostic power for stenotic AVFs. This study showed that AVF stenosis can be detected during HD with a moderate-to-excellent accuracy using Qa measurement by BTM as screening procedures.




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